Structure and dielectric studies of Sn4+/Er3+ co-doped BaTiO3 nano-powders

Abstract

Nanocrystalline barium titanate (BTO3) powders annealed at 1050 °C for 4 h, were synthesized using the sol-gel method and the effects of Sn4+/Er3+ co-doping (BTSO3:2Er) on microstructure and dielectric properties of BTO3 powders, were investigated. The crystalline structure, microstructure, molecular structure, and dielectric properties were investigated using X-ray powder diffraction, field emission scanning electron microscope, with energy dispersive X-ray analysis, the Fourier transform infra-red spectroscopy, and dielectric spectrometer. X-ray powder diffraction analysis confirmed the formation of both BTO3 and BTSO3:2Er in a single tetragonal phase. For BTSO3:2Er sample, the particle size decreased from 64 for pure BTO3 to 57.11 nm for BTSO3:2Er, inhibiting grain growth upon co-doping with Sn4+/Er3+ ions. Further, according to field emission scanning electron microscope observations, the Fourier transform infra-red spectroscopy analysis showed a new band assigned to M-O. Correspondingly, BTSO3:2Er showed an anomaly relaxation peak whose maximum was positioned at temperature value (174 °C) higher than the Curie temperature (TC) according to permittivity measurements. Its TC shifted from 125 to 103 °C and permittivity considerably increased to become ten times greater than that of pure BTO3, revealing enhancements of dielectric properties upon doping with Sn4+/Er3+ ions. Also, AC conductivity for BTSO3:2Er sample considerably increased due to the formation of excess oxygen vacancies.